1. Field of the Invention
The present invention relates to a mounting arrangement for the exchangeable attachment of a probe stylus or a probe styli combination on a probe for a coordinate measuring installation, which mounting arrangement is constituted from an electrically-operating clamping device with a permanent magnet and an electromagnet wherein the field from the electromagnet is superimposed on the field from the permanent magnet, and whereby a connecting member of the probe stylus or the probe styli combination is drawn through the intermediary of the clamping device against a bearing or support in the mounting member therefore on the probe which determines its position.
2. Discussion of the Prior Art
An exchangeable mounting or attachment for a probe stylus of the above-mentioned type is currently known from the disclosure of European Pat. No. 0 128 464. This known mounting arrangement possesses an isostatic three-point support, against which the contact plate for the probe stylus, which plate is assembled from three parts, is drawn by the electromagnetic clamping device. This three-part contact plate is constituted of steel. For an automatically-controlled probe exchange, the electromagnetic is supplied with direct current, as a result of which there is generated a magnetic field whose magnitude generally corresponds to that from the inserted permanent magnet; however, whose direction is opposite thereto. In view thereof, the resultant overall magnetic field becomes almost zero. Because of this superposition, the restraining force between the magnets and the three-part plate disappears, whereupon the probe styli combination is released from the mounting member with the aid of plate springs.
The assembly of the connecting member with the probe styli combination is relatively complex because of the three plates which are in connection with each other. In addition, there is encountered the necessity for employing plate springs in order to be able to displace the magnet components against the cover of a housing upon the elimination of the magnetic field from the permanent magnet, as a result of which there is formed the necessary air gap in order to be able to remove the probe styli combination from the probe housing. In this known holder for changing the probe stylus it is necessary to provide a relatively large number of individual parts, which must presently be coordinated with each other in order to afford an untroubled acceptable functioning.